Calenders



R. THOMAS Nov. 3, 1964 CALENDERS 4 Sheets-Sheet 1 Filed Dec. 24, 1962INVENTOR.

Rex THOMAS ATTORNEYS Nov. 3, 1964 R. THOMAS & 9

CALENDERS Filed Dec. 24, 1962 4 Sheets-Sheet 2 I nw 10 M 25 2 IHIIHINVENTOR.

Rex THOMAS BY v %www/4 4 &

ATTORNEYS R. THOMAS CALENDERS Nov. 3, 1964 4 Sheets-Sheet 3 Filed Dec(24, 1962 INVENTOR. Rex THOMAS i A TTORNE YS R. THOMAS 3,155,029

CALENDERS 4 Sheets-Sheet 4 Nov. 3, 1964 Filed Dec. 24, 1962 INVENTOR RexTHOMAS A TTORJVE YS United States Patent O &1555929 CALENDERS RexThomas, Terrasse Vandreuil, Quebec, Canada, as-

signor to Dominion Engineering Works Limited, Montreni, Quebec, CanadaFiled Dec. 24, 1962, Ser. No. %6,784 Claims priority, application CanadaNov. 2'2, 1962 6 Claims. (Ci. lihi-170) This invention relates tocalender stacks and more particularly to open-side calender stacks asused in the p per making and other industries for calendering materialin sheet, web, or strip form.

Although this invention is described as embodied in a cflender stack foruse in the paper making industry, it will be understood that theprinciples and features described herein may be employed in calendersdesigned :for use in `the textile, p las-tic and other industries, whereregulation of the calender roll nip-pressure is an important factor.

One conventional method for obtaining relief of nip pressures in closedcalender stacks, includes fluid diaphrag-ms positioned on the tops ofthe roll bearing housings. When pressure is applied to these fluiddiaphragms, upward lifting forces are exerted on the roll bearinghousings positioned immediately above.

A disadvantage inherent in this method is tha-t the whole system isinterdependent. The reactions to the nip-relieving -pressures aretransferred to the hearing .housings immediately below and, as thiseffect is cumulative, the lower roll bearings support the resultant loadfrom all the nip-relievng pressures, resulting therefore in excessivehearing and fluid diaphragm sizes.

Another disadvantage is that the procedure of removing rolls from thecalender stack is extremely complicated.

Another known method for obtaining partial relef of nip pressures inclosed calender stacks, includes two p-airs of vertical tubes arrangedwithin the calender frame columns, one pair being positioned on eachside of the calender. The upper ends of the tubes are connected toistons within fluid pressure cylinders, and attached to the lower endsof each pair of tubes is a yoke which car- -ries a roll hearing housing.Mounted coaxially within thetubes are sha-fts, which are also connectedat their upper ends to pistons within fluid pressure cylinders. These shafts project below the lower ends of the tubes and also carry yokes'adjustably positioned between each pair of sha fts for mounting rollhearing housings thereon@ Thus the stack of-rolls is divided into twosections and it is possible to vary the nip-pressures between eachsection of rolls by varying the pressures in the fluid cylinders.

The maindisadvantage with this method is that this system becomesobjectionably. complexif .the stack is required to be divided into morethan two sections, making it impract-icable, therefore, to obtainnip-relief on all rolls. v e

Another disadvantage is that large diameter interme- 'diate rolls arerequired at the stack divisions.,

A further conventional method for obtaining relief of nip-pressures inopen-side calender stacks, includes arms :pivotal-ly mounted at theirmici-positions on the calender frames. The roll bear-ing housings aremounted on ,one end of the arms and, attheir op posite ends, the armsare connected to air diaphragms which are operably connecte on theopposite endof the arms. a

To facilitate roll lifting, for separation of nips, etc., links areconnected between each hearing housing with ;of the calender.

the upper bearing housing links connected to lifting means. Slots in.the links allow for roll separation when the rolls are lifted. In thisconventional nip-relieving arrangement, the lifting links and thenip-pressure relieving diaphragms, are both mounted outside the calenderfrarne structure.

A disadvantage in the last mentioned conventional method is that thebearng housings, being positioned between the connecting links, arethemselves utilized as connecting means. Therefore, when rolls areremoved from the stack for re-grnding purposes, etc., it is necessary toinstall longer conneoting links to replace the bearing hous ings of theremoved rolls.

Another di sadvantage is that the roll removal procedure is complicatedby the need to remove mechanical 'links and pins in order to d isconnectthe hearing housings from hearing housings immediately above and beow.

A further disadvantage is that the air diaphragms are Very bulkyandproject beyond the calender fra-me structure, therefore being verysusceptible to dama-ge. k

It is the main object of this invention to provide, in an open-sidecalender, a mechanism which performs the functions of roll lifting,nip-relieving and nip-loading, and in which the said mechanism istotally enclosed in the calender frame structure.

Another object is to provide a mechanism which permits the calender tobe operated with less than the full number of roll-s in the stack applying nip-pressures, without the need for additional roll littingequipment.

Another object is to provide an .open-side calender in whichintermediate rolls may be removed from the stack, without the need fordisconnect-ing the roll lifting mechansm.

Another object is to improve the efliciency of roll removal in open-sidecalenders by providing a calender design featuring no obstruction abovethe roll stack.

A further object is to provide an enclosed and compact open-sidecalender design, providing improved 'ap-` pearance and permitting moreeflicient operation.

These .objectives are embodied in this invention by providing a calenderroll nip-pressure regulatin-g means which includes pivotally mountedlever arms mounted in pair-s, one arm of each pair being mounted on eachside A calender rol-l is supported between the ends of the arms on oneside of their p ivots, and the ends' of the armsrcmote from the calenderroll are connected to vertical-ly extending and vertically movableoperating members, by means' of fluidpressure responsive devices. Thefluid pressure responsive devices 'are arran ged to exert Upward ordownward pressure on the calender roll by applying, respectively,downward or upward pressures on the ends of the arms remote from thecalender roll. r

The vertical-ly extending and vertically mova ble operting members arealso arranged to open the nip-s between the calender rolls, from thetopof the stack pro gressively downwards, whenlthe Operating membersaremoved progressively downwards. A These. features are characterized inthe preferred execution of this invention by mounting each calenderroll, above the'bottomor king roll, on -the ends of arms pivotallymounted on the calender frarne structure. The ends of the pivotailymounted arms remote from' the calender rolls are connected to vertcaloperating orlifting screws, positioned one on each side of the calender,by means of fluid cylinder and piston devices, the ends of the armsbeing connected to piston'rods attached to the Pistons and the head-endsof the cyiinders being atjtache d to the lifting screws bymeans ofpositioning brackets Pressure fluid applied to either the head-ends orthe red-ends of the fluid cylinders provides either,

&155329 downward or upward forces respectively on the ends of thepivotally mounted arms, resulting in either decrease or increase in thecalender roll nip-pressure&

The lifting screws are threaded externally and the positioning bracketsare threaded internally and adjustably positioned on the lifting screws,to provide progressively increasing distances, from the top calenderroll position downwards, between the pistons in the fluid cylinders andthe head-ends of the fluid cylinders. Separation of the calender rollnips is accomplished by lowering the lifting screws by means ofscrewjacks. This results in the exhaustion of the fluid above thepistons in the uppermost cylinders, whereupon the pistons bottom at thehead-ends of the cylinders to form solid links between the liftingscrews and the arms. Further lowering of the lifting screws forces theends of the pivotally mounted arms, which are connected to the pistonrods, downwards, therefore lifting the top roll. The positioning of thepositioning brackets on the lifting screws provides for progressivelifting of the rolls, from the top to the bottom of the stack, as thelifting screws are lowered still further.

An alternative arrangement of this invention provides onlyfor relief ofthe nip-pressures and uses the same basic arrangement as used in thepreferred execution, except that the pivotally mounted arms eachcomprise two members, each member being pivotally` mounted on the samepivot. The two arm members have nnilateral abutments which contact toprovide a lifting force on the roll when a downward force is applied tothe end of the arm member which is attached to the piston rod in thefluid cylinder and piston device. The unilateral abutments are free toseparate to allow the roll to be lii'ted by means other than thecylinder and piston device, such as when a lump of paper stock passesthrough the roll nip.

A preferred embodiment of this invention is illustrated by way ofexample in the accompanying drawings i for accomplishingroll lifting.

FIG. 5 is a part sectional view, showing details of an alternativearrangement of the present invention.

' FIG. 6 is a sectional plan View taken on 6-6 in FIG. 5.

FIG. 7 is a hydraulic circuit diagram, showing the equipment and pipingarrangement for the preferred execution. r

FIG. 8 is a hyd'aulic circuit diagram, showing the equipment and pipingarrangcment for an alternative xecuton.

Refet'- now to FIGS. 1 to 6, with the understanding that only one sideof the calender assembly has been illustrated and that the Componentshereinafter described are duplicated for the side of the calender notshown.

-Lifting screw 10 is slidably mounted for vertical movement-in calender'vertical frame 11 and is threaded over 'a large proportion .of itslength. Lifting screw 18 may be lifted or lowered by means of screwjack12, which 'is coupled to lifting screw 10 by means of coupling 13 andoperated by drive means 14. The output screw 15 of screwjack`12 is keyedfor non-rotation. Crossshaft 16' transmits synchronized Operating torqueto the screwjack (not shown) on the other side of the calender. By thismeans, the lifting and lowering motions of lifting screws 16' oneachside of the calender, aresynchronized. Liftng screw 1% is slidablyjonrnaled at itsupper end in bushing 17, which is positioned in theupper part of the calender vertical frame 11.

Pivot arms 18 are pivotally mounted on calender vertical frame 11 bymeans of pivot pins 19 and mounting brackets 29. calender rolls 21 arejournaled in bearings and housings 22, which are rigidly attached toflanges 23 of pivot arms 18.

The clevis-ends 24 of pivot arms 13, extend alternately to positions oneither side of lifting screw 10. FIG. 3 shows alternate pivot arms 25.Fluid cylinders 26 are attached at their red-ends to clevis-ends 24 ofpivot arms 18 and 25, and at their head-ends to positioning brackets 27.Positioning brackets 27 are mounted on liting screw 16 and are threadedinternally to correspond with the thread on liiting screw IG.Positioning brackets 27 are assembled to position fluid cylinders 26alternately on either side of lifting screw 10, and are locked inposition by locknuts 28.

In accordance with the above arrangement when fluid pressure is appliedto the head-ends of the pisto-ns within cylinders 26, downward forcesare exerted on the clevisends 24 of pivot arms 13 and 25, which, throughpivot pins 19, apply upward lifting forces to hearing housings 22.Similarly, fluid pressure applied to the rod-ends of the pistons withincylinders 26, applies downward forces to hearing housings 22. Spacers 29maintain the relative positions between mounting brackets 20.

Calender base frames 30 (one on each side of the calender), supportcalender vertical frames 11 and carry screwjacks 12 and bearings andhousings 31, which journal the bottom calender roll 32.

All connections to fluid cylinders 26 are located within the calendervertical frames 11, removable panels 33 providing access to the fluidconnections and to` facilitate adjustrnent of positioning brackets 27,etc.

In the alternative arrangement shown in FIG. 5 and 6, the pivot arm isin two parte, lever arm 34 and mounting arm 35. The turning momentexerted by lever arm 34 on mounting arm 35, is transmitted throughcontacting surfaces 36.

Contacting surfaces 35 are unilateral abutments. Thus, although alifting force may be ap'plied to hearing housings 22 by fluid cylinders26, hearing housings 22 are free to move upwards under the influence ofany external force, such as a wacl of paper passing through the nips,etc., without aecting the position of lever arm 34. i

To study the operation of this invention, refer now to FIGS. 1, 2, 3 and7, which show-the mechanical arrangement and basic pressure fluidcircuit diagram for the preferred execution.

To obtain relief of nip-pressures between calender rolls' V 21, fluidunder pressure is applied to the head-ends of cylinders 26. Thisproduces turning moments about pivot pins 19 and results in Upwardlifting forces exerted on the rolls. To increase the nip-pressuresbetween calender rolls 21, fluid under pressure is applied to therod-ends of cylinders 26, which reverses the nip-relieving action and Vprovided for each roll, one at each end, and are controlled in parallel.

Nip-relief between calender rolls 21 is obtained by moving 4-way3-position manual control valve41 to the left, which is the cross-overposition. Fluid under` pressure enters pressure reducing valve 37, whichis regulated to` give the required roll nip-relief using pressure gage40 passes through manual control valve 41 and on tojthe head-end ofcylinder 26. This produces a downward act-" corresponding roll 21 willalso commence to lift.

ing force on piston 43 in cylinder 26, which results in an upwardlifting force acting on roll 21.

Increased loading between calendar rolls 21 is obtained by moving 4-way3-postion manual control valve 41 to the right, which is thestraight-through position. Fluid under pressure enters pressure reducingvalve 37, which is regulated to the required pressure using pressuregage 49, passes through manual control valve 41 and on to the rod-end ofcylinder 26. This produces an upward lifting force on piston 43, whichresults in a downward acting force on roll 21.

Should an extra thick wad of paper pass through the nips duringnip-loading, pressure fluid in the space beneath piston 43 in cylinder26, will be suddenly increased. This increase in pressure will beimmediately relieved through pressure relief valve 39 to tank 42.Pressure relief valve 39 is set to operate at a pressure consistent withcomponent strength.

The preferred execution shown in FIGS. l, 2, 3 and 7, while designedprimarily to enable the loading between the nips to be increased ordecreased to suit ditfering conditions of Operations, this sameexecution can be used solely for increasing the nip loading or solelyfor decreasing the nip loading.

Refer now to FIGS. 5, 6 and 8, which show an alternative execution ofthis invention, in which fluid cylinders 26 are operable for relief ofnip-pressures only.

Relief of nip-pressure between rolls 21 is obtained by moving 4-way2-position manual control valve 44 downward, thus providing athrough-path for the pressure fluid. Fluid under pressure enterspressure reducing valve 37, which is regulated to the requirednip-relieving pressure using pressure gage 49, passes through manualcontrol valve 44 and on to the head-end of cylinder 26. This produces adownward acting force on piston 43 in cylinder 26, and results in anupward lifting force on roll 21.

Refer now to FIG. 4, which is a schematic diagram showing the basicOperating sequence for roll lifting, as applied to both the preferredand alternative executions.

An essential feature of the roll lifting procedure is the fact thatpositioning brackets 27 are positioned on lifting screws 18 to provideprogressively increasing distances, from the top roll positiondownwards, between pistons 43 within fluid cylinders 26 and thehead-ends of fluid cylinders 26. These distances are shown as A in FIG.4.

As lifting screws 10 are lowered by means of screwjacks 12, the fluid inthe upper cylinders 26 is exhausted to tank 42 and the pistons bottom atthe head-ends, forming solid links between pivot arms 18 and positioningbrackets 27. Thus, further lowering of lifting screws 10 produceslifting of the upper roll 21. As the lowering progresses still further,pistons 43 in the cylinders 26 next down from the top, will bottom," andthe It is thus seen that the progressively increasing distances betweenthe pistons 43 and the head-ends of cylinders 26, result in successivelifting of the rolls and produce the required gaps between the rollswhen lifted, as shown at D' in FIG. 4.

This method of roll lifting can also be used to reduce the number ofactive nips in the stack, by lowering lifting screws I'll, lifting therolls and separating the nips, until the desired number of rolls remainin contact.

From the preceding description, it is seen that rolls may be simplyremoved from the stack without the need for disconnecting and removinglinks or lifting mechanisms from the hearing housings. At the same time,roll removal is facilitated by the fact that no roll lifting equipmentis located above the roll stack.

A further feature of this invention is the fact that the combination ofthe mechanisms for roll lifting, niprelieving and nip-loading into oneset of Components, which is totally enclosed in the vertical calenderframe,

enables all pipings and connections to be located within the enclosedframe. This provides an unobstructed and compact assembly resulting inincreased operator elficiency and, at the same time, the enclosed systemand piping arrangements are protected from damage and kept free ofaccumulated dirt.

What I claim is:

1. A roll stack calender including vertically movable shafts, means forraising and lowering said shafts, valve controlled fluid pressureactuated nip-pressure regulating roll supporting means connected betweensaid shafts and one or more of the calender rolls located above thebottom or king roll, said nip-pressure regulating means being operableindependently of said shafts to apply upward pressure to the connectedroll to decrease the load or nippressure at the nip between said rolland the next lower roll and being also operable independently of saidvertically movable shatts to apply downward pressure to the connectedroll to increase the load or nip-pressure at said nip, said calenderbeing further characterized in that downward movement of said shaftsresults in upward movenment of all the calender rolls connected to saidshafts through the agency of said nip-pressure regulating rollsupporting means.

2. A roll stack calender including intermediately pivoted lever armscarrying calender rolls at one end thereof and having their other endsdirectly connected to vertically movable shafts through cylinder andp-iston devices, said cylinder and piston devices constituting fluidpressure actuated valve controlled nip-pressure regulating meansoperable independently of said shafts to apply upward pressure to theconnected roll to decrease the load or nippressure at the nip betweensaid roll and the next lower roll and being also operable independentlyof said movable shafts to apply downward pressure to the connected rollto increase the load or nip-pressure at said nip, and means for loweringand raising said shafts, said calender being further characterized inthat downward movement of said shafts results in upward movement of allthe calender rolls connected to said shafts through the agency of saidnip-pressure regulating roll supporting means.

3. A roll stack calender including vertically movable shafts, means forraising and lowerng said shafts, valve controlled fluid pressureactuated nip-pressure regulating roll supporting means connected betweensaid shafts and one or more of the calender rolls located above thebottom or king roll, said nip-pressure regulating roll supporting meansincluding intermediately pivoted lever arms mounted in pairs, each ofsaid pairs .of lever arms having a calender roll mounted between theends thereof on one side of their intermediate pivots and a connectionto the vertically movable shats from the remaining ends of said leverarms said connection comprising fluid pressure responsive cylinder andpiston devices, the pistons of said devices being connected to saidremaining ends of said leverarms and the cylinders of said devices beingconnected to said vertically movable shafts, the cylinder and pistondevices of said nip-pressure regulating means being operableindependently of said shafts to apply up- Ward pressure to the connectedroll to decrease the load or nip-pressure at the nip between said rolland the next lower roll and being also operable independently of saidvertically movable shafts to apply downward pressure to the connectedroll to increase the load or nip-pressure at said nip, said calenderbeing further characterized in that downward movement of said shaftsresults in upward movement of all the calender rolls connected to saidshafts through the agency of said cylinder and piston devices.

4. A roll stack calender including vertcally movable shafts, means forraising and lower-ing said shafts, valve controlled fluidpressureactuated nip-pressure regulating roll supporting means connectedbetween said shafts and one or more of the calender rolls located abovethe bottom or king roll, said nip-pressure regulating roll sup-'co-Operating 'pai 1s, each of said lever arni assemblies comprising twolever arm sections having adjacent ends thereof pivotlly mounted on acommon pivot and extendng outwardly from said common pivot in opposingdirections, the outer ends of similar lever arm sections in each of saidpairs of lever arm assemblies being connected to said vertically movableshafts and the outer cnds of the other lever arm sections in said pairssupporting the ends of said calender roll, said adiacent ends of saidlever arm sections in each of said lever arm assemblies having co actinghorizontal stop faces such that downward pressure on the ends of saidlevel' arm sections connected to said shafts produces Upward pressure onthe ends of said levet' .arm sections supporting the ends of saidcalender roll,

Whilst at the same time leaving said calender roll free to move upwardlywhen any lumps of paper stock or like objects pass through the nipbetween said calender roll and the next lower calender roll in saidstack, said calender being further characterized in that downwardmovement of said shafts results in an Upward movement of all thecalender rolls connected to said shafts through the agency of saidnip-pressure regulating roll supporting means.

5. A roll stack calender as set forth in claim 4 in which the connectionbetween the outer ends of similar lever arm sections and said shaftscomprises fluid pressure responsive cylinder and pisten devices, theistons of said devices being connected to the outer ends of said similarlever arm sections and the cylinders of said devices being connected tosaid shafts.

6. A roll stack calender as set fo'th in claim 4 including a calenderframe and in which each of said lever arm assemblies is internediatelypivoted on said calender frame.

References cited' in the file of this patent UNITED STATES PATENTS1,934,233 Malkin Nov. 7, 1933 2,300,994 Thiele et al Nov. 3, 19422,8SO,952 Hornbostel Sept. 9, 1958 2,98S,1G0 Hornbostel May 23, 19612,992,866 Cavalieri July 18, 1961 FOREIGN PATENTS 523,866 Germany Api'.29, 1931 794531 France Dec. 12, 1935 %08,317 Germany July 12, 19511,054,953 Germany Apr. 16, 1959

1. A ROLL STACK CALENDER INCLUDING VERTICALLY MOVABLE SHAFTS, MEANS FORRAISING AND LOWERING SAID SHAFTS, VALVE CONTROLLED FLUID PRESSUREACTUATED NIP-PRESSURE REGULATING ROLL SUPPORTING MEANS CONNECTED BETWEENSAID SHAFTS AND ONE OR MORE OF THE CALENDER ROLLS LOCATED ABOVE THEBOTTOM OR KING ROLL, SAID NIP-PRESSURE REGULATING MEANS BEING OPERABLEINDEPENDENTLY OF SAID SHAFTS TO APPLY UPWARD PRESSURE TO THE CONNECTEDROLL TO DECREASE THE LOAD OR NIPPRESSURE AT THE NIP BETWEEN SAID ROLLAND THE NEXT LOWER ROLL AND BEING ALSO OPERABLE INDEPENDENTLY OF SAIDVERTICALLY MOVABLE SHAFTS TO APPLY DOWNWARD PRESSURE TO THE CONNECTEDROLL TO INCREASE THE LOAD OR NIP-PRESSURE AT SAID NIP, SAID CALENDERBEING FURTHER CHARACTERIZED IN THAT DOWNWARD MOVEMENT OF SAID SHAFTSRESULTS IN UPWARD MOVEMENT OF ALL THE CALENDER ROLLS CONNECTED TO SAIDSHAFTS THROUGH THE AGENCY OF SAID NIP-PRESSURE REGULATING ROLLSUPPORTING MEANS.